Axial piston rotary power device

ABSTRACT

An axial piston rotary power device can be configured as a four-cycle and two-cycle internal combustion engine, a compressor, a pump, a fluid-driven motor or an expander. The device includes an external stator housing, an internal axial stator and a rotary cylindrical block attached to an end shaft that can rotate within the annular enclosure formed by the two stators. The cylindrical block contains a plurality of cylindrical cavities arranged as pairs of working cylinders. Each cylindrical cavity encloses a double-acting piston assembly comprising two piston heads connected to a middle portion having a pair of axially spaced apart roller cam followers that make roller contact with a guide cam surface protruding from the inside of the external stator housing. The action of the cam roller followers on the guide cam imparts rotation to the cylindrical block when the piston assemblies reciprocate within their respective bores.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of the inventor's U.S. Ser.No. 09/977,633 filed on Oct. 15, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to axial piston rotary power devices having one ormore pistons disposed parallel to and displaced from an axis ofrotation. More particularly, the invention relates to internalcombustion engines, pumps, compressors, expanders, fluid driven motors,compressor driven internal combustion engines, and fluid drivencompressors. It additionally relates to any such devices that differ ina simple structural modification of a central cylindrical stationarymember, cam profile and end plate ports.

2. Background Information

This invention relates to rotary power devices of the type having aplurality of cylinders arranged around and parallel to a central axis ofrotation in an equally-spaced relationship, and in which pistonsdisposed within the cylinders cooperate with a cam track to impartrotational motion to a rotor when the pistons reciprocate in theirrespective cylinders. Examples of rotary devices of the above type canbe found in United States patent specifications such as U.S. Pat. No.5,813,372 of Manthey; U.S. Pat. No. 4,287,858 of Anzalone; U.S. Pat. No.Re. 30,565 and U.S. Pat. No. 4,157,079 of Kristiansen; U.S. Pat. No.5,209,190 of Paul; U.S. Pat. No. 5,103,778 of Usich, Jr.; U.S. Pat. No.5,253,983 of Suzuki, et al.; U.S. Pat. No. 5,323,738 of Morse; U.S. Pat.No. 4,213,427 of Di Stefano; and U.S. Pat. No. 1,614,476 of Hutchinson.Although such power devices have been proven to be theoreticallyfunctional, they are characterized in some respects by complexitiesassociated with the arrangements of cams and of intake and dischargemeans, which make them costly to manufacture, assemble, and maintain.Furthermore, the apparatus of the present invention represents one ormore improvements over a device described in the inventor's pending U.S.patent application Ser. No. 09/977,633, filed on Oct. 15, 2001, thedisclosure of which is herein incorporated by reference.

BRIEF SUMMARY OF THE INVENTION

An axial piston rotary power device of the invention comprises a statorportion and a rotor portion having a rotatable shaft extending along anaxis of the device. The stator portion of the device comprises anexternal stator portion defining a generally cylindrical interiorbounded by a back plate portion and a front plate portion that has acentral throughhole within which the rotatable shaft is journaled. Amiddle portion of the external stator is preferably formed from a pairof diagonally-split mating elements. In addition, the stator comprises acylindrical internal stator portion projecting from the back plateportion into the cylindrical interior along the axis of the device so asto define an annular space extending between the internal and externalstator portions. The internal stator portion has a plurality ofpassageways within it, each of the passageways comprising a channelparallel to the axis and each of the channels communicating with atleast one respective radially oriented port formed in the internalstator at a respective selected axial position. Yet another staticportion of a preferred device is an axially undulating guide tracksurface that may comprise a surface protruding inwardly, by apredetermined amount, from the annular internal wall of the middleportion of the external stator of the device.

The rotor portion of the device comprises a cylindrical block having amedial annular cutout portion extending through its outer surface so asto form an annular recess. The block is fixedly attached to the shaftand rotatable within the annular space between the internal statorportion and the external stator portion and is arranged so that aprotruding guide track surface attached to or forming a portion of themiddle portion of the external stator fits into the annular cutout. Thisblock has a central cylindrical bore adapted to receive the internalstator, and also includes a selected number of cylindrical cavitiesparallel to the axis of the device and spaced apart from that axis by asingle selected radial distance. Each of the cylindrical cavities isdivided into a pair of working cylinders axially separated from eachother by a portion of the annular cutout. Each of these cylindricalcavities has a radially inwardly directed end opening adjacent each ofits two ends. One of these end openings is associated with a workingcylinder in the first set thereof and may communicate with the centralcylindrical bore at a first selected axial position. The other endopening in each cylindrical cavity is associated with the associatedworking cylinder of the second set and may communicate with the centralcylindrical bore at a second selected axial position. Alternatively,working cylinders of the first set may comprise respective end openingscommunicating with the central bore at one selected axial position, andworking cylinders of the second set may comprise axial end openingscommunicating with passages formed in one of the end plates of theexternal stator.

It will be recognized that either working cylinder arrangement can bedescribed in terms of two sets of working cylinders aligned parallel tothe axis of the device, wherein each of the sets comprises a circulararray and wherein each cylinder in one set is axially aligned with arespective one of the working cylinders in the other set.

In addition, the annular surface of the cutout portion of thecylindrical block may include an equal number of axial cam groovesextending between ones of each pair of working cylinders. In anoperating configuration, each pair of axially opposed working cylindersslidably receives a respective piston assembly. Each of the pistonassemblies comprises two opposed cylindrical piston heads fixedlycoupled by a middle portion which preferably comprises a pair of axiallyspaced apart roller cam followers receiving the protruding cam guide. Inaddition, the middle portion of the piston assembly preferably includesa detachable cam pin follower slidably engaging the cam groove. All ofthe roller cam followers engage the undulating protruding guide surfaceso as to couple a rotary motion of the block to the reciprocatingtranslational motions of the pistons. If the pistons are driven to andfro within the cylinders by known means such as the expansion of anexplosive air-fuel charge, or by the introduction of a pressurizedworking fluid, the rotary power device of the invention can function asan internal combustion engine, a fluid-driven compressor, a compoundinternal combustion and compressor, a fluid-driven motor or expanderdevice providing output shaft power. Conversely, if the block is rotatedby the application of a torque to the input shaft, the rotary powerdevice of the invention can function as a pump or compressor.

One embodiment of the present invention provides an improved sparkignition rotary internal combustion engine which operates in afour-cycle mode and which overcomes problems presently encountered inthe class of rotary engine having pistons positioned parallel to eachother around a common axis of rotation. Another embodiment of thepresent invention provides an improved rotary internal combustion enginewhich operates in a two-cycle mode and which overcomes problemspresently encountered in the class of rotary engines having pistonspositioned parallel to each other around a common axis of rotation.

Another feature of a preferred rotary power device of the invention isthat it can be easily converted to a different type of rotary powerdevice by a simple modification or replacement of a central stationarymember, cam profile or front end plate. Thus, one can convert aninternal combustion engine of the invention into a rotary power devicethat can act as any one of a pump, a compressor, a fluid-driven pump, afluid-driven compressor, a fluid-driven motor and an internalcombustion-driven compressor

A preferred embodiment of the invention provides a rotary power devicehaving valveless ports.

A feature of some embodiments the invention is that they are light inweight, small in size and have a reduced part count when compared withprior art rotary power devices.

A benefit of some embodiments of the invention is that they provide arotary power device that closely approximates continuous intake,compression, combustion and discharge processes.

Another benefit of some embodiments of the invention is that theyprovide a rotary power device characterized by reduced noise andvibration.

Although it is believed that the foregoing recital of features andadvantages may be of use to one who is skilled in the art and who wishesto learn how to practice the invention, it will be recognized that theforegoing recital is not intended to list all of the features andadvantages. Moreover, it may be noted that various embodiments of theinvention may provide various combinations of the herein before recitedfeatures and advantages of the invention, and that less than all of therecited features and advantages may be provided by some embodiments.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is an exploded isometric view of a four-cycle rotary powerdevice.

FIG. 2 is an isometric view of a four-cycle rotary power device of FIG.1 having quarter portions cut away from the rotor and an external statorfor purposes of illustration.

FIG. 3 is an isometric view of the rotor-piston assembly of the rotarypower device of FIG. 1, the view having portions cut away for purposesof illustration.

FIG. 3a is an isometric view of an alternative rotor-piston assembly ofthe rotary power device of FIG. 1 having portions cut away for purposesof illustration

FIG. 4 is an exploded isometric view of the cam and external stator ofthe four-cycle rotary power device of FIG. 1 having the upper camportion cut away for purposes of illustration.

FIG. 4a is an exploded isometric view of the cam and external stator ofthe four-cycle rotary power device employing the alternativerotor-piston assembly of FIG. 3a and having the upper cam portion cutaway for purposes of illustration.

FIG. 5 is an isometric view of the internal stator of the rotary powerdevice of FIG. 1 functioning as a four-cycle internal combustion engine.

FIG. 5s is a side elevation view of the internal stator of FIG. 5.

FIG. 5a is a sectional view taken along line 5 a—5 a of FIG. 5s.

FIG. 5b is a sectional view taken along line 5 b—5 b of FIG. 5s.

FIG. 6 is an exploded isometric view of the piston assembly of therotary power device of FIG. 1.

FIG. 7 is an isometric view of rotary power device of FIG. 1.

FIG. 7s is a side elevation view of the rotary power device of FIG. 7.

FIG. 7e is an end view of the rotary power device of FIG. 7.

FIG. 8 is a sectional view taken along line 8—8 of FIG. 7e.

FIG. 9a is a sectional view taken along line 9 a—9 a of FIG. 7s.

FIG. 9b is a sectional view taken along line 9 b—9 b of FIG. 7s.

FIG. 10 is an isometric view of an alternative internal stator of therotary power device of FIG. 1, the device operating as a four-cyclepump, four-cycle compressor, four-cycle fluid-driven motor or four-cycleexpander device.

FIG. 10s is a side elevation view of the alternative internal stator ofFIG. 10.

FIG. 10a is a sectional view taken along line 10 a—10 a of FIG. 10s.

FIG. 10b is a sectional view taken along line 10 b—10 b of FIG. 10s.

FIG. 10c is an isometric view of an alternative internal stator of therotary power device of FIG. 1 employing the rotor-piston assembly ofFIG. 3a and the external stator of FIG. 4a, the device operating as acompound four-cycle internal combustion engine or fluid compressordevice.

FIG. 10d is an isometric view of an alternative internal stator of therotary power device of FIG. 1 employing the rotor-piston assembly ofFIG. 3a and the external stator of FIG. 4a, the device operating as afour-cycle fluid-driven compressor device.

FIG. 10e is an isometric view of an alternative front end plate of thealternative external stator of FIG. 4a functioning as internalcombustion-driven or fluid-driven compressor device.

FIG. 10f is an end view of the alternative front end plate of FIG. 10e.

FIG. 11 is an isometric view of an alternative two-cycle rotary powerdevice operating as an internal combustion engine, the view having anportion of the rotor and external casing cut away for purposes ofillustration.

FIG. 11a is an isometric view of an alternative two-cycle rotary powerdevice operating as a compound internal combustion engine or acompressor, the view having portions of the rotor and external casingcut away for purposes of illustration

FIG. 12 is an isometric view of a rotor-piston assembly of the rotarypower device of FIG. 11, the view having portion of rotor cut away forpurposes of illustration.

FIG. 12a is an isometric view of rotor-piston assembly of the rotarypower device of FIG. 11a, the view having portions of the rotor cut awayfor purposes of illustration

FIG. 13 is an exploded isometric view of an alternative cam and externalstator for a two-cycle power device, the view having a portion cut awayfor purposes of illustration.

FIG. 13a is an exploded isometric view of an alternative cam andexternal stator for a two-cycle power device, the view having a portioncut away for purposes of illustration.

FIG. 14 is an isometric view of the rotary power device of FIG. 11.

FIG. 14s is a side elevation view of FIG. 14.

FIG. 14e is an end view of the rotary power device of FIG. 14.

FIG. 15 is a sectional view taken along line 15—15 of FIG. 14e.

FIG. 16a is a sectional view taken along line 16 a—16 a of FIG. 14s.

FIG. 16b is a sectional view taken along line 16 b—16 b of FIG. 14s.

FIG. 17 is an isometric view of the internal stator of the rotary powerdevice of FIG. 11.

FIG. 17s is a side elevation view of the device of FIG. 17.

FIG. 17a is a section view taken along line 17 a—17 a of FIG. 17s.

FIG. 17b is a section view taken along line 17 b—17 b of FIG. 17s

FIG. 17c is a section view taken along line 17 c—17 c of FIG. 17s

FIG. 17d is a section view taken along line 17 d—17 d of FIG. 17s

FIG. 17e is a section view taken along line 17 e—17 e of FIG. 17s.

FIG. 18 is an isometric view of an alternative internal stator of therotary power device of FIG. 11, the device operating as two-cycle pump,compressor, fluid-driven motor or expander device.

FIG. 18s is a side elevation view of FIG. 18.

FIG. 18a is a sectional view taken along line 18 a—18 a of FIG. 18s.

FIG. 18b is a sectional view taken along line 18 b—18 b of FIG. 18s.

FIG. 18c is a sectional view taken along line 18 c—18 c of FIG. 18s.

FIG. 19 is an isometric view of the front plate of the rotary powerdevice of FIG. 11a.

FIG. 19e is an end view of the front plate of FIG. 19.

FIG. 20a is an alternative isometric view of an internal stator of therotary power device of FIG. 11a, the device operating a compoundtwo-cycle compressor and internal combustion engine.

FIG. 20b is an alternative isometric view of an internal stator of therotary power device of FIG. 11a, the device operating as fluid drivencompressor.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-9, illustrate the principles of this invention in embodimentsconfigured as a four-cycle internal combustion engine. FIGS. 11-17illustrate the principles of this invention in embodiments configured asa two-cycle internal combustion engine. A complete reading of thedisclosure will lead one skilled in the art will to understand thatthese same principles can be successfully employed to yield otherdevices, such as four-cycle and two-cycle pumps, compressors,fluid-driven motors, fluid-driven compressors, expander devices, andinternal combustion-driven compressors. These devices are as shown inFIGS. 3a, 4 a, 10, 10 a-f, 11 a, 12, 12 a, 18, 19, 20 a and 20 b,respectively, comprise a simple modification or replacement of thecentral stationary member and/or end front plate.

Referring to FIGS. 1-9, a depicted embodiment of the rotary power device10 of the invention comprises a stationary housing 20 having a generallycylindrical interior. The housing, or external stator 20, preferablycomprises a middle portion comprising diagonally split cylindricalhalves, comprising an upper half 12 a and lower half 12 b, forming agenerally cylindrical interior that is closed off at its ends by a frontend plate 14 a, having a central throughhole opening 16 a, and a backend plate 14 b, having a central throughhole 16 b. The diagonally splitblock can be joined along a line that is a diagonal of the cylindricalblock

In some embodiments an end plate 14 a, as shown in FIG. 4a, may comprisefour circular arcuate passages 29 a, 29 b, 29 c and 29 d formed into theinner surface of the plate (e.g., by a cutting operation) and connectedto respective ports 31 a, 31 b, 31 c, and 31 d. These passages maycomprise two diagonally opposed fluid intake passages alternated by twodiagonally opposed discharge passages. Furthermore, the middle portionsof the halves may be aligned by means of alignment pins 17 andcorresponding holes 19, and preferably include a multiplicity of coolingpassages 15 through which a coolant medium may be circulated by usingappropriate intake and discharge ports (not shown). In addition, thelower middle portion 12 b preferably includes a passage 23 connected toa port 21 for supplying or withdrawing lubricant, which may serve as aninternal cooling fluid in addition to providing a lubricating function.The end plates 14 a and 14 b are preferably secured to the middleportions 12 a and 12 b of the stationary housing by tie rods and boltsor other known fastening means (not shown). A generally cylindricalinternal stator 50 extends along an axis 13 of the device into theinterior of the housing 20 from the end plate central opening 16 b andis fixedly attached to the back end plate 14 b by bolts or othersuitable fastening means (not shown).

A protruding cam is disposed within the cylindrical housing 20 andpreferably comprises a pair of diagonally mating portions comprising anupper portion 18 a and a lower portion 18 b. Each cam portion, as shownin FIG. 4, is preferably formed as an inward surface protrusionextending from an inner surface of a middle portion of the housing 20and having axially undulating guide track surfaces. In a four-cycledevice, the cam surface comprises a first pair of points at which theguide track surface is a maximum distance from the back end plate 14 b,and a second pair of points at which the guide track surface is aminimum distance from the back end plate 14 b. These minima and maximaare disposed in alternating fashion.

The central internal stator 50, as shown in FIG. 1 and FIG. 5,preferably comprises a cylindrical portion 52 extending coaxiallythrough the interior, and an end flange portion 54 for fixedly attachingthe stator to the end back plate 14 b. Furthermore, the cylindricalportion 52 is preferably provided with four lateral cutout openingsforming one pair of angularly adjacent intake and discharge ports 56 a,58 a that are axially spaced apart from a similar second pair ofangularly adjacent intake and discharge ports 56 b, 58 b. The two pairs56 a, 58 a; 56 b, 58 b of ports are arranged to have a 90° angular phaseshift relative to each other. Each port cutout opening is defined withinan angular extension of approximately 90° and has an angularly varyingradial depth profile. These lateral openings communicate with axialintake circular channels 62 and discharge annular channel 60. Inalternative embodiment (not shown) the intake ports communicate with anannular channel 60 and the discharge ports communicate with a circulardischarge channel 60. A first ignition port 66 a is disposedapproximately diametrically opposite to a corresponding angularlyadjacent pair of intake and discharge ports 56 a, 58 a. A second,similar, ignition port 66 b is disposed diametrically opposite to theintake and discharge ports 56 b, 58 b. These ignition ports 66 a and 66b are connected to axial channels 64 a and 64 b and may comprise meansfor receiving igniters 76 a, 76 b, which may comprise spark plugsscrewed into a threaded portion of the channel. An annular recess 70 fordistribution of lubricant may also be provided in the internal statorportion 52 which is adapted to receive lubricant from port 74communicating with axial channel 68. Furthermore, two recesses 72 may beprovided in order to receive sealing rings (not shown) that wouldenclose the lubricating recess 70.

The rotor-piston assembly 40 is disposed in the generally annular spaceformed between the internal stator 50 and the inner wall of the externalstator 20. This assembly 40, as shown in FIG. 3, comprises a cylindricalblock 22 having a medial annular cutout or recess portion 24 enclosedbetween a pair of multiplicity of axially oriented working cylindricalbores 26 a and 26 b. Each of the working cylinders is parallel to andpreferably equidistant from the axis 13 of the device and the workingcylinders are preferably spaced at equal angular intervals surroundingthe central bore 28. Furthermore, the working cylinders 26 a and 26 bhave inner end opening through the annular recess 24 and outer endopenings closeable by cover ring plates 30 a and 30 b, respectively,that may be retained by fixture means (not shown). The lateral surfaceof the annular recess 24 may include a multiplicity of axial cam grooves42 extending axially between two axially opposed working cylinders. Therotor assembly 40 preferably includes an axial shaft 38 fixedly attachedto one end of the cylindrical block 22 and rotatably journaled within abearing means 55 supported in the front end plate 14 a. The shaft 38extends outwardly through the end plate central opening 16 a fortransmitting output shaft power in versions of the rotary power devicethat are configured as engines and for receiving an input torque inversions of the rotary power device that are configured as pumps orcompressors. In the example depicted in the drawing, there are twelvecylindrical cavities 45 disposed parallel to each other and to the axisof rotation of the shaft 38. Each cylindrical cavity 45 comprises a pairof working cylinder 26 a and 26 b, each of which has respective radiallyinward openings 32 a and 32 b disposed adjacent their respective outerends and communicating with the central bore 28. Alternatively, as shownin FIG. 3a, the working cylinders 26 a adjacent the front plate, insteadof having a radially inward end opening, may have an axial end openingthrough the front ring plate 30 a that communicates with channels 29 a,29 b, 29 c and 29 d in the front end plate.

A reciprocating piston assembly 100, as shown in FIGS. 1, 2, 3 and 6,may be axially disposed within the annular recess having opposedcylinder heads, each slidingly engaging respective pistons in respectiveworkings cylinders 26 a and 26 b. Each piston assembly comprises twoopposed cylindrical heads 80 a and 80 b fixedly coupled by a middleportion 84. The middle portion preferably includes a pair of axiallyspaced apart roller cam followers 82 a and 82 b supported bycorresponding brackets 88 a and 88 b and by pins 90 a and 90 b. Theseroller cam followers make roller contact with the surfaces of theprotruding cam track portions 18 a and 18 b. The middle portion 84further includes a slot opening 92 adapted to receive a cam follower pin86 for slidably engaging the axial cam groove 42 in the rotor annularrecess. Ring recesses 94 a and 94 b may be provided to receive ringseals (not shown) in each piston head.

An understanding of the operation of the rotary power device 10 of theinvention as a four-cycle internal combustion engine may be gained byreference to the depiction of FIGS. 5a, 5 b, 8, 9 a, and 9 b. Thisengine may be started by means of a starter motor (not shown)temporarily connected to the shaft 38 to initiate the rotation of therotor assembly 40. Fluid pressure forces are transmitted from the headsof piston assemblies 100 to respective roller can followers 82 a and 82b that are in rolling contact with the protruding cam track surfaces 18a and 18 b to result in a normal reaction force. The tangentialcomponents of the normal reaction forces of these contact forces aretransmitted to the axial cam groove 42 by means of cam follower pin 86thereby developing a torque causing the rotation of the rotor assembly.At the same time, the piston assemblies 100 reciprocate in theirrespective working cylinders 26 a and 26 b. A step-by-step analysis ofthe process may begin with by recourse to a limiting position in whichone working cylinder, say 26 a, of a pair thereof is at its minimumoperating volume. This exemplar starting position corresponds to theso-called top dead center (TDC) in a conventional engine. In thisarrangement the working cylinder 26 a is bounded by one piston head 80 aand end cover plate 30 a. As the piston element starts moving away fromthe end wall 30 a it uncovers an end opening 32 a in the respectivecylinder, and an air/fuel mixture charge is drawn into the cylinder fromthe intake port 56 a of the internal stator 50 as the rotor assembly 40completes the first 90° of angular displacement. At this point thevolume reaches a maximum, corresponding to the first bottom dead center(BDC) position in a conventional engine. During the second 90° ofangular displacement of the rotor assembly, the piston head 80 a startsmoving back toward the end wall 30 a while the end opening 32 a isblocked by the wall portion 52 of the internal stator 50, therebycompressing the air/fuel mixture to a minimum volume, corresponding tothe second (TDC) position. At the beginning of the third 90° of angulardisplacement of the rotor assembly, the end opening 32 a aligns itselfwith ignition port 66 a so that a spark from a spark plug 76 a caninitiate combustion and power expansion. After the expansion the volumereaches its second maximum corresponding to the second (BDC) position ina conventional engine. During the fourth 90° of angular displacement ofthe rotor assembly, the opening 32 a registers with the discharge port58 a as the piston head 80 a moves toward the end wall 30 a, therebydischarging combustion products as the piston moves towards its secondTDC. The other end of the piston assembly 100 performs an identicalcycle but with a 90° phase shift. For example, as one of the workingcylinders in a cylindrical cavity 45 performs an intake stroke thepaired working cylinder performs a compression stroke. As illustrated inFIGS. 9a-9 b, the present rotary engine comprises two sets of workingcylinders aligned parallel to the axis of the device, wherein each ofthe sets comprises a circular array and wherein each working cylinder inone set is axially aligned with a respective one of the workingcylinders in the other set, each set comprising twelve working cylindersperforming, in one revolution of the rotor assembly, the equivalent oftwenty-four cylinders in two revolutions of the conventional four-cyclespark ignition engine.

A rotary power device of the invention may be cooled by means of primaryand secondary cooling systems. The primary cooling system may comprise alubricating fluid, such as oil, that is forced through an axial channel68 in the internal stator, conveyed by radial port 74 to the lubricatingannular recess 70, and finally by means of lubricating holes 36 ingroove cam 42 to the piston assemblies and rotor external surfaces. Thelubricating fluid in the groove cam 42 is forced by the effect ofcentrifugal forces and friction forces to the protruding cam surfaces,working cylinder internal surfaces and into the clearance gap betweenthe rotor exterior surfaces and inner surfaces of the external stator20. The lubricating fluid may be removed by means of a port 21 in thelower middle portion 12 b of the external casing and then cooled by anexternal secondary cooling loop (not shown) before returning back to thechannel 68. Also, a secondary cooling fluid such as water, may be usedby circulating it through jacket cooling passages 15 in the externalcasing 20. The use of primary and secondary cooling system permits theheat transfer from the primary lubricating cooling fluid to thesecondary non-lubricating cooling fluid.

The rotary power device can be easily converted to serve a differentpurpose other than the internal combustion engine by replacing theinternal stator 50 with a modified internal stator Referring to FIG. 10,10 s, 10 a and 10 b, a rotary power device employing a modified centralstator 50 a can function as any one of a motor-driven compressor orpump, a fluid-driven motor, and an expander device operating infour-cycle mode. In this configuration, the internal stator comprisestwo sets of intake and discharge ports, where each set is defined in oneplane transverse to the axis 13 and is axially spaced apart from asecond plane that includes the second set. Moreover, each set is inalignment with respective working cylinders end opening 32 a and 32 b ofthe rotor assembly. Each set thus comprises two diagonally opposedintake ports alternated by another two diagonally opposed dischargeports. Each set forms a 90° angular displacement relationship withrespect to the other set. Each intake and discharge ports is definedwithin approximately a 90° angular displacement. The four intake ports56 a, 56 b, 56 c, and 56 d communicate with a common central axialintake conduit 62, while the four discharge ports 58 a, 58 b, 58 c, 58 dcommunicate with the annular channel 60. Alternately, (not shown) thefour intake ports may communicate with the annular channel 60 while thefour discharge ports communicate with the central channel 62.

In the operation of the device depicted in FIGS. 10a-10 b, as the rotorassembly completes one revolution, each piston assembly end performsfour strokes, which comprise two intake strokes alternated by twodischarge strokes. As one end of one piston assembly performs an intakestroke, the other end of the same piston assembly performs a dischargestroke. In functioning as a motor-driven pump or compressor, the rotorassembly is made to rotate by coupling the end shaft to a driving meanssuch as a motor (not shown). The pistons reciprocate in response to theaction of cam followers on the protruding cam surfaces, while endopenings 32 a and 32 b of the working cylinders alternately registerwith intake and discharge ports of the internal stator 50 a, thusperforming intake and discharge functions. Alternately, the rotarydevice employing the internal stator shown in FIG. 10 may function as afour-cycle fluid-driven motor or expander device. In such operatingmode, a pressurized fluid is received in the axial intake channel 62 andsubsequently routed to the operative ends of working cylinders 26 a and26 b, thus transmitting an axial force through the piston heads andrespective roller cam followers 82 a and 82 b. The tangential componentof the reaction forces between the cam rollers and the protruding camsurfaces 18 a and 18 b is transmitted through the cam pin 86 in camgroove 42 to impart a torque on the rotor assembly, thus causing therotation of the assembly. At the same time, reciprocation of the pistonsresults in discharging the depressurized fluid through channel 60 duringthe discharge phase of the cycle.

Still another embodiment of the four-stroke rotary power device is onethat serves as a four stroke compound internal combustion engine and asa fluid compressor. This is accomplished by replacing the rotor assembly40 with a modified rotor assembly 40 a. The modified rotor assemblycomprises a circular array of working cylinders 26 b, each of whichcommunicates with the central bore through a respective end opening 32b. The rotor assembly further comprises a second circular array ofworking cylinders 26 a communicating through axial end openings 33 withfour circular arc channels 29 a, 29 b, 29 c and 29 d embedded in theadjacent front plate 14 a of the external stator. Further, in thisembodiment, the internal stator 50 is replaced with a modified internalstator 50 b, as shown in FIG. 10c. The modified stator 50 b comprisesone intake port 56, one exhaust port 58 and an ignition port 66, eachport communicating with end openings 32 b in the circular array 26 b ofworking cylinders. In operation, each working cylinders in the circulararray 26 b performs four strokes comprising intake, compression, powerand discharge strokes as the rotor completes one revolution. Incontrast, each working cylinders of the first set 26 a function as afluid compressor executing two fluid intake strokes alternated by twodischarge strokes whereby axial end opening 33 alternately communicatewith end plate intake passages 29 a and 29 c and discharge passages 29 band 29 d.

In addition to the above applications, the four-stroke rotary powerdevice can be easily converted to serve as a four stroke fluid-drivencompressor, pump or pressure exchanger device. In this application theexternal stator 20 is replaced with modified external stator 20 a, asshown in FIG. 4a. Also, the rotor assembly 40 is replaced with themodified rotor assembly 40 a of FIG. 3a. The modified rotor assemblycomprises set of working cylinders 26 b communicating with the centralbore through respective end openings 32 b. The rotor assembly furthercomprises a second set of working cylinders 26 a communicating throughaxial end openings 33 with four circular arc channels 29 a, 29 b, 29 cand 29 d embedded in the adjacent front plate 14 a of the externalstator. Also, the internal stator 50 is replaced with internal stator 50c, as shown in FIG. 10d, which comprises two diametrically opposedintake ports 56 b and 56 d alternated by two diametrically opposedexhaust ports 58 b and 58 d, each port communicating with end openings32 b in one set 26 b of working cylinders. In operation, a highlypressurized fluid is conveyed to one set of working cylinders, say 26 b,through an internal stator axial intake channel 62, and is thendischarged through an exhaust channel 60. A second weakly pressurizedfluid is conveyed to the second set of working cylinders 26 a throughend plate ports 31 a and 31 d connected to respective intake channels 29a and 29 d and is discharged through channels 29 b and 29 c connected torespective ports 31 b and 31 c. An alternative arrangement (not shown)is possible wherein the highly pressurized fluid is conveyed to thefirst set 26 a of working cylinders and the weakly pressurized fluid isconveyed to the other set 26 b. The highly pressurized net fluid forcesin one set of working cylinders is transmitted through pistons and camtracks to cause rotation of the rotor and the pressurization of theweakly pressurized fluid in the second set of working cylinders. In thisembodiment, each working cylinder perfumes two intake strokes alternatedby two exhaust strokes.

Turning now to FIGS. 11-17, one finds an embodiment of the inventionthat can operate as a two-cycle internal combustion engine. Thetransformation of the four-cycle device previously disclosed to atwo-cycle rotary internal combustion includes the followingmodifications. First, the two-cycle protruding cam 18 a and 18 b of FIG.4, comprising two minima and two maxima points, is replaced with a onecycle cam track of FIG. 13 comprising one minimum point and one maximum.With this modification each end of a piston assembly performs twostrokes when the rotary assembly completes one revolution. Secondly,unlike the four-cycle rotary assembly case in which the end openings 32a and 32 b perform both intake and exhaust functions, the two strokeengine of FIG. 11 comprises an additional pair of radially inward medialopenings 34 a and 34 b, as depicted in FIG. 12. These medial openingsare used only for the exhaust function, and the radially inward endopenings 32 a and 32 b are used solely for intake. Thirdly, the internalcentral stator 50 is replaced with a modified central stator 50 d shownin FIG. 17.

The modified internal central stator 50 d as shown in FIG. 17 for atwo-cycle internal combustion engine is similar to the internal stator50 used in the four-cycle engine except for the disposition and angularextent of the intake and exhaust ports. In the two-cycle internal stator50 d, a pair of axially spaced apart intake ports and discharge ports 56a and 58 a communicate with corresponding aligned openings 32 a and 34 aof the first set 26 a of working cylinders. Correspondingly, a pair ofaxially spaced apart intake and discharge ports 56 b and 58 bcommunicate with aligned openings 32 b and 3 b of the second set 26 b ofworking cylinders. To allow for purging of combustion products in thisso called scavenging process, the exhaust port is made to have a widerangular displacement so that is overlaps the axially adjacent intakeport. Secondly, each pair of axially adjacent intake and discharge portsis disposed at 180° relative to the other pair. In addition, theignition ports 66 a and 66 b of the four-cycle engine are replaced withinjection ports 66 a and 66 b in the two-cycle engine. As depicted inFIG. 16a and 16 b, an injection port 66 a is disposed diagonallyopposite to an intake port 56 a, and similarly as injection port 66 b isdiagonally opposite its associated intake port 56 b. Axial channels areprovided, as in the four-cycle engine, to connect these ports to theexterior. Intake ports 56 a and 56 b may communicate with an annularaxial channel 62 and exhaust ports 58 a and 58 b may communicate with anannular channel 60. Alternately, (not shown) the intake ports 56 a and56 b may communicate with an annular axial channel 60 and the exhaustports 58 a and 58 b may communicate with the annular axial channel 62. Acommon central axial channel 64 provides injection charges to injectionports 66 a and 66 b, respectively. The lubricating recess 70 receiveslubricating cooling primary fluid through an axial channel 68, and ringseal recesses 72 are adapted to receive ring seals (not shown).

The principle of imparting torque on the rotor is the same as in thefour-cycle case. The tangential components of the reaction contactforces between roller cam followers 82 a, 82 b and the protruding camsurfaces 18 a, 18 b are transmitted through the cam pin 86 on the groovecam 42 to provide a rotating moment to the rotor. The resulting rotationof the rotor causes the piston assemblies to reciprocate in theirrespective working cylinders. Because of the one-cycle cam profile, eachend of the piston assembly performs two strokes as the rotor movesthrough a single complete revolution. Each stroke of a piston assemblycomprises a predominantly compression stroke at one end and apredominantly power stroke at the opposing end. As shown in FIGS. 17a-17d, the exhaust phase is defined over an angular extent including aportion subsequent to the power stroke and another portion preceding thecompression stroke, while the intake phase includes an angular extentoverlapped by an exhaust phase.

The operation of a two-cycle power device as an internal combustionengine is illustrated with respect to the internal stator 50 d by meansof FIG. 17a through 17 d. When one of the working cylinders approaches aminimum volume position, injection and auto-ignition occur through ports66 a and 66 b. At the same time, the axially opposite working cylinderis approaching its maximum volume position whereby exhaust followed bypurging of products of combustion by portion of the intake air takesplace. In the purging operation, the intake port 56 a and 56 b overlapswith the respective exhaust port 58 a and 58 b. Because of the largerangular displacement of the discharge port, a portion of the intake airis used to displace leftover products of combustion in the so-calledscavenging process while the remainder is used for compression.

In addition to the internal combustion engine embodiment discussedabove, a two-cycle rotary power device of the invention can serve as apump, compressor, fluid-driven motor or an expander device by replacingthe central internal stator member with a stator of the sort shown inFIG. 18. The internal stator 50 e depicted in FIGS. 18, 18 s, 18 a and18 b comprises one pair of axially spaced apart intake ports 56 a, 56 bcommunicating with the central intake channel 62, and a second pair ofaxially spaced apart discharge ports 58 a, 58 b communicating with anannular discharge channel 60. Alternatively, (not shown) the internalstator 50 d may comprise one pair of axially displaced intake ports 56a, 56 b communicating with an annular intake channel 60, and a secondpair of axially displaced discharge ports 58 a, 58 b communicating witha central discharge channel 62. Each port is defined within 180° ofangular displacement, and each angularly adjacent pair of intake anddischarge ports forms a 180° phase angular relationship with respect tothe other axially displaced pair. In functioning as a pump orcompressor, the rotor assembly is made to rotate by coupling the endshaft 38 to a driving means such as a motor (not shown). The pistonassemblies, in response to the action of roller cam followers onprotruding cam surfaces, reciprocate while openings 32 a and 32 b inrespective working cylinders alternatively register with correspondingintake ports (56 a, 56 b) and discharge ports (58 a, 58 b) of theinternal stator 50 e, thus performing intake and discharge functions.Each time the rotor completes a 180° angular displacement, each pistonassembly completes one stroke, performing a simultaneous intake strokein one circular array of working cylinders and a discharge stroke in theother array of working cylinders. In functioning as a fluid-drivenmotor, pressurized fluid received in the axial intake channel 62 isrouted to respective ends of working cylinders to cause thereciprocation of the pistons assemblies 100 in respective workingcylinders. At the same time, the action of the roller cam followers 82 aand 82 b on the protruding cam surfaces 18 a, 18 b imparts a torque onthe rotor assembly. In the process, potion of the fluid pressure energyis converted into mechanical rotational energy through the shaft andanother portion remains as residual energy in the discharging fluid.

Still another embodiment of the present invention is a rotary powerdevice that can serve as a two-cycle compound internal combustion engineas shown in FIGS. 11a and 12 a. In this embodiment a first set ofworking cylinders 26 a communicates with the exterior through axial endopening 33 within the working cylinders. Each end opening 33 alternatelycommunicates with semicircular intake and discharge channels 29 a and 29b. These channels are cut into the inner face of the front plate 14 a,and each channel has a respective intake and discharge port 31 a and 31b. The second set of working cylinders 26 b communicates with theinternal stator 50 f, as shown in FIG. 20a, through radial openings 32,34 and functions as a two-cycle internal combustion engine while thefirst set of working cylinders 26 a serve as a two-cycle compressor.

Alternatively, the above device can serve as a two-cycle fluid-drivencompressor by replacement of the internal stator 50 f with anotherinternal stator 50 g shown in FIG. 20b. In this case, a first array ofworking cylinders 26 a communicates with the exterior though axial endopening 33 within the working cylinders. Each end opening 33 alternatelycommunicates with semicircular intake and discharge channels 29 a and 29b. The second array of working cylinders 26 b comprises respective endradial openings 32 that alternately register with an intake port 56 anda discharge port 58 of the internal stator 50 g. In functioning as afluid-driven compressor, a higher pressure fluid supplied to one set ofworking cylinders may be used to compress or pump a second fluid oflower pressure supplied to the second set of working cylinders.

As will be understood by those skilled in the art, various embodimentsother than those described in detail in the specification are possiblewithout departing from the scope of the invention will occur to thoseskilled in the art. It is, therefore, to be understood that theinvention is to be limited only by the appended claims.

What is claimed is:
 1. An axial piston rotary power device comprising astator portion and a rotor portion, the rotor portion comprising arotatable shaft extending along an axis of the device, the statorportion comprising: an external stator portion defining a generallycylindrical interior; the external stator portion comprising a middleportion, a back plate portion forming one of two ends of the generallycylindrical interior, and a front plate portion forming the second endof the generally cylindrical interior, the front plate portion having acentral throughhole within which the rotatable shaft is journaled; acylindrical internal stator portion projecting from the back plateportion into the cylindrical interior along the axis of the device so asto define an annular space extending between the internal and externalstator portions, the internal stator portion having a plurality ofpassageways formed therein, at least one of the passageways comprisingan inlet passageway, at least one of the passageways comprising anexhaust passageway, each of the passageways comprising a channelparallel to the axis, at least two of the channels communicating with atleast one respective radial port formed in the internal stator portionat a respective selected axial position; and an axially undulating guidesurface extending into the annular space from the middle portion of theexternal stator portion; the rotor portion further comprising: acylindrical block fixedly attached to the shaft, the block rotatablewithin the annular space between the internal stator portion and theexternal stator portion, the block comprising a medial annular recessfor receiving the axially undulating guide surface, the block comprisinga central cylindrical bore for receiving the internal stator, the blockfurther comprising a selected number of cylindrical cavities parallel tothe axis of the device and spaced apart therefrom by a single selectedradial distance, each cavity comprising an axially spaced pair ofworking cylinders, each working cylinder having a respective medial endcommunicating with the annular recess and a respective closeable outerend adjacent a respective one of the front plate and back plate portionsof the external stator portion, at least one working cylinder in eachpair thereof having a radially inwardly directed end opening adjacentthe respective outer end thereof, each of the end openings communicatingwith the central cylindrical bore at a selected axial position; and theselected number of piston assemblies, each piston assembly slidablyreceived in a respective one of the cylindrical cavities; each pistonassembly having a respective piston head at each of two ends thereof anda respective middle portion extending between the two piston heads, eachpiston assembly comprising at least one respective pair of rotatableroller cam followers for following the axially undulating cam tracksurface, each piston assembly further comprising a respective camfollower pin for slidably engaging a respective axial groove formed in awall of the respective cylindrical cavity.
 2. The axial piston rotarypower device of claim 1 wherein the axially undulating guide surfacecomprises a protruding portion of an inner surface of the middle portionof the external stator.
 3. The axial piston rotary power device of claim1 wherein the axially undulating guide surface comprises two separateportions attached to each other along a line extending diagonally acrossthe cylindrical block.
 4. The axial piston rotary power device of claim1 wherein: the axially undulating cam surface comprises a first pair ofpoints at which the surface is a maximum distance from the back plateand a second pair of points at which the surface is a minimum distancetherefrom; the first of each pair of working cylinders has a respectivefirst radially inwardly directed end opening adjacent a respective outerend of the respective first cylinder, each of the first end openingscommunicating with the central cylindrical bore at a first selectedaxial position; the second of each pair of working cylinders has arespective second radially inwardly directed end opening adjacent arespective outer end of the respective second cylinder, each of thesecond end openings communicating with the central cylindrical bore at asecond selected axial position; the at least one inlet passagewaycomprises at least two inlet ports, each of the first and second endopenings communicating exactly once with one of the two inlet portsduring the course of each rotation of the block; the at least oneexhaust passageway comprises at least two exhaust ports, each of thefirst and second end openings communicating exactly once with one of thetwo exhaust ports during the course of each rotation of the block; andthe plurality of passageways further comprises two ignition passageways,a first of the ignition passageways comprising a first ignition port atthe first selected axial position, the first ignition port communicationwith each first end opening exactly once during each rotation of theblock, the second of the ignition passageways comprising a secondignition port at the second selected axial position, the second ignitionport communicating with each second end opening exactly once during eachrotation of the block, wherein each of the ignition ports comprisesmeans for receiving a respective igniter; whereby the axial pistonrotary power device is adapted to function as a four-cycle internalcombustion engine.
 5. The four-cycle rotary power device of claim 4wherein the passageways comprise exactly one inlet passageway andexactly one exhaust passageway, one of the inlet and exhaust passagewayscomprising an axial channel, the other of the inlet and the exhaustpassageways comprising an annular channel disposed about the axialchannel.
 6. The four-cycle rotary power device of claim 4 wherein themeans for receiving an igniter comprises a threaded region of therespective ignition port.
 7. The axial piston rotary power device ofclaim 1 wherein the axially undulating guide surface comprises a firstpair of points at which the surface is a maximum distance from the backplate and a second pair of points at which the surface is a minimumdistance therefrom; the first of each pair of working cylinderscomprises a respective first radially inwardly directed end openingadjacent a respective outer end of the respective first cylinder, eachof the first end openings communicating with the central cylindricalbore at a first selected axial position; the second of each pair ofworking cylinders has a respective second radially inwardly directed endopening adjacent a respective counter end of the respective secondcylinder, each of the second end openings communicating with the centralcylindrical bore at a second selected axial position; the at least oneinlet passageway comprises first and second diagonally opposed radialinlet ports at the first selected axial position, each of the first andsecond radial inlet ports communicating with each first end openingexactly once during each rotation of the block, the at least one inletpassageway further comprising third and fourth diagonally opposed radialinlet ports at the second selected axial position, each of the third andfourth radial inlet ports communicating with each second end openingexactly once during each rotation of the block; and the at least oneexhaust passageway comprises first and second diagonally opposed exhaustports at the first selected axial position, each of the first and secondexhaust ports communicating with each first end opening exactly onceduring each rotation of the block, the at least one exhaust passagewayfurther comprising third and fourth diagonally opposed exhaust ports atthe second selected axial position, each of the third and fourth exhaustports communicating with each second end opening exactly once duringeach rotation of the block; wherein the axial piston rotary power deviceis adapted to function as one of a four-cycle pump, a four-cyclecompressor, a four-cycle fluid-driven compressor and a four-cyclefluid-driven motor.
 8. The four-cycle rotary power device of claim 7wherein the passageways comprise exactly one inlet passageway andexactly one exhaust passageway, one of the inlet and exhaust passagewayscomprising an axial channel, the other of the inlet and the exhaustpassageways comprising an annular channel disposed about the axialchannel.
 9. The axial piston rotary power device of claim 1 wherein theaxially undulating cam surface comprises a first pair of points at whichthe surface is a maximum distance from the back plate portion and asecond pair of points at which the surface is a minimum distancetherefrom; the first of each pair of working cylinders comprises arespective radially inwardly directed end opening adjacent one of thetwo end plate portions, each of the radially inwardly directed endopenings communicating with the central cylindrical bore at the selectedaxial position; the second of each pair of working cylinders comprises arespective axial end opening communicating with the second of the twoend plate portions; the at least one inlet passageway comprises a pairof diagonally opposed radial inlet ports, each of the radial inlet portscommunicating with each of the radially inwardly directed end openingsexactly once during each rotation of the block; the at least onceexhaust passageway comprises a pair of diagonally opposed radial exhaustports, each of the radial exhaust ports communicating with each of theradially inwardly directed end openings exactly once during eachrotation of the block; the plurality of passageways further comprisesone ignition port for receiving an igniter, the ignition portcommunicating with each radially inwardly directed end opening exactlyonce during each rotation of the block; and wherein the second end plateportion further comprises: two diagonally opposed fluid intakepassageways, each of which communicates with each of the axial endopenings exactly once during each rotation of the block; and twodiagonally opposed fluid exhaust passageways, each of which communicateswith each axial end opening exactly once during each rotation of theblock; whereby the axial piston rotary power device is adapted tofunction as a compound four-cycle internal combustion engine driving afluid compressor.
 10. The axial piston rotary device of claim 9 whereinthe passageways in the second end plate portion comprise a first and asecond diagonally opposed circular arc intake passageway alternated by athird and a fourth diagonally opposed circular arc exhaust passageway,each of the first through fourth circular arc passageways comprising arespective groove formed in the inner face of the second end plateportion, each of the first through fourth circular arc passagewaysconnected to a respective port.
 11. The axial piston rotary power deviceof claim 1 wherein the axially undulating guide surface comprises afirst pair of points at which the surface is a maximum distance from theback plate and a second pair of points at which the surface is a minimumdistance therefrom; a first of each pair of working cylinders comprisesa respective radially inwardly directed end opening adjacent a first ofthe end plate portions, each of the radially directed end openingscommunicating with the central cylindrical bore at the selected axialposition; the second of each pair of working cylinders comprises arespective axial end opening extending through its closeable outer end,each axial end opening communicating with a passage in the second endplate portion; the at least one inlet passageway comprises a pair ofdiagonally opposed radial inlet ports, each of the inlet portscommunicating with each of the radially directed end openings exactlyonce during each rotation of the block; the at least one exhaustpassageway comprises a pair of diagonally opposed radial exhaust ports,each of the exhaust ports communicating with each of the radiallyinwardly directed end openings exactly once during each rotation of theblock; and wherein the second end plate portion comprises: twodiagonally opposed fluid intake passageways, each fluid intakepassageway communicating with each axial end opening exactly once duringeach rotation of the block; and two diagonally opposed fluid exhaustpassageways, each of the fluid exhaust passageways communicating witheach axial end opening exactly once during each rotation of the block;whereby the axial piston rotary power device is adapted to function asone of a four-cycle fluid-driven compressor and a four-cyclefluid-driven pump.
 12. The axial piston rotary device of claim 11wherein: the passageways in the second end plate portion of the externalstator comprise first and second diagonally opposed circular arc intakepassages alternated by third and fourth diagonally opposed circular arcexhaust passages; each of the circular arc passageways comprises arespective groove formed in an inner face of the second end plateportion of the external stator; and each circular arc passageway isconnected to a respective port.
 13. The axial piston rotary power deviceof claim 1 wherein: the axially undulating guide surface comprisesexactly one point at which the surface is a maximum distance from theback plate portion and exactly one point at which the surface is aminimum distance therefrom; each of the cylindrical cavities comprisesfour axially spaced radially inwardly directed openings, each of theopenings communicating with the central cylindrical bore at acorresponding one of four selected axial positions, wherein the firstand the fourth of the axial positions are respectively adjacent the twoend plate portions of the external stator, wherein the second axialposition is intermediate the first and the third positions and whereinthe third position is intermediate the second and the fourth positions;the at least one inlet passageway comprises an air inlet passagewaycomprising a first radial air inlet port at the first of the fourselected axial positions, the first radial air inlet port communicatingwith the first radial opening in each cylindrical cavity exactly onceduring each rotation of the block, the at least one air inlet passagewayfurther comprising a second radial air inlet port at the fourth selectedaxial position, the second radial air inlet port communicating with thefourth of the radial openings in each cylindrical cavity exactly onceduring each rotation of the block; the at least one exhaust passagewaycomprises a first exhaust port at the second axial position, the firstexhaust port communicating with the second radial opening in eachcylindrical cavity exactly once during each rotation of the block, and asecond exhaust port at the third selected axial position, the secondexhaust port communicating with the third radial opening in eachcylindrical cavity exactly once during each rotation of the block; andthe plurality of passageways further comprises at least one fuelinjection passageway comprising at least one fuel injection channel andat least two fuel injection ports, a first fuel injection port disposedat the first selected axial position diagonally opposite the first inletport, the first fuel injection port communicating with each first radialopening exactly once during each rotation of the block, the second ofthe fuel injection passageways comprising a second fuel injection portdisposed at the fourth axial position diagonally opposite the secondinlet port, the second fuel injection port communicating with eachfourth radial opening exactly once during each rotation of the block;whereby the axial piston rotary power device is adapted to function as atwo-cycle internal combustion engine.
 14. The two-cycle rotary powerdevice of claim 13 comprising exactly one inlet passageway, exactly oneexhaust passageway and one axial fuel injection passageway, each of theinlet and exhaust passageways comprising respective channels disposedabout the axial fuel injection channel.
 15. The axial piston rotarypower device of claim 1 wherein: the axially undulating guide surfacecomprises exactly one point at which the surface is a maximum distancefrom the back plate portion and exactly one point at which the surfaceis a minimum distance therefrom; each working cylinder in each pairthereof comprises a respective radially inwardly directed openingadjacent a respective outer end thereof, each of the radially inwardlydirected openings communicating with the central cylindrical bore at arespective one of a first and a second selected axial positions; the atleast one inlet passageway comprises a first radial inlet port at thefirst selected axial position, the first radial inlet port communicatingwith the respective radially inwardly directed opening in a first ofeach pair of working cylinders exactly once during each rotation of theblock, the at least one inlet passageway further comprising a secondradial inlet port at the second selected axial position, the secondradial inlet port communicating with the respective radially inwardlydirected opening in the second of each pair of working cylinders exactlyonce during each rotation of the block; and the at least one exhaustpassageway comprises a first exhaust port at the first selected axialposition, the first exhaust port communicating with the respectiveradially directed opening in each of the first of each pair of workingcylinders exactly once during each rotation of the block, the at leastone exhaust passageway further comprising a second exhaust port at thesecond selected axial position, the second exhaust port communicatingwith the respective radially directed opening in each of the second ofeach pair of working cylinders exactly once during each rotation of theblock; whereby the axial piston rotary power device is adapted tofunction as one of a two-cycle pump, a two-cycle compressor, and atwo-cycle fluid-driven motor.
 16. The two-cycle rotary power device ofclaim 15 comprising a single inlet passageway and a single exhaustpassageway, one of the inlet and exhaust passageways comprising an axialchannel, the other of the inlet and the exhaust passageways comprisingan annular channel disposed about the axial channel.
 17. The axialpiston rotary power device of claim 1 wherein: the axially undulatingguide surface comprises exactly one point at which the surface is amaximum distance from the back plate and exactly one point at which thesurface is a minimum distance therefrom; the first of each pair ofworking cylinders comprises a respective first radially inwardlydirected end opening adjacent the outer end thereof, each of the firstradially inwardly directed openings communicating with the centralcylindrical bore at a first selected axial position; the first of eachpair of working cylinders further comprises a respective second radiallyinwardly directed opening axially spaced apart from the respective firstradially inwardly directed end opening, wherein each of the secondradially inwardly directed end openings communicates with the centralcylindrical bore at a second selected axial position more distal from afirst of the two end plate portions than is the first selected axialposition; the second of each pair of working cylinders comprises arespective axial end opening extending through the closeable outer endthereof, each of the axial end openings communicating with at least thesecond of the two end plate portions of the external stator; the atleast one inlet passageway comprises a first radial air inlet port atthe first selected axial position, the first radial air inlet portcommunicating with each of the first radially inwardly directed openingsexactly once during each rotation of the block; the at least one exhaustpassageway comprises a first exhaust port at the second selected axialposition, the first exhaust port communicating with each of the secondradially inwardly directed openings exactly once during each rotation ofthe block; the plurality of passageways further comprises one fuelinjection passageway comprising a fuel injection port disposed at thefirst selected axial position diagonally opposite the first inlet port,said injection port communicating with each of the first radial inwardlydirected openings exactly once during each rotation of the block; andwherein the second end plate portion further comprises: a fluid intakepassageway communicating with each axial end opening exactly once duringeach rotation of the block; and a fluid exhaust passageway communicatingwith each axial end opening exactly once during each rotation of theblock; whereby the axial piston rotary power device is adapted tofunction as a compound two-cycle internal combustion engine and fluidcompressor.
 18. The axial piston rotary device of claim 17 wherein thefluid intake and fluid exhaust passageways comprise semicircular groovesformed in an inner face of the second end plate portion of the externalstator.
 19. The axial piston rotary power device of claim 1 wherein: theaxially undulating guide surface comprises exactly one point at whichthe surface is a maximum distance from the back plate and exactly onepoint at which the surface is a minimum distance therefrom; the first ofeach pair of working cylinders comprises a respective radially inwardlydirected opening adjacent a first of the two end plate portions of theexternal stator, each of the radially inwardly directed openingscommunicating with the central cylindrical bore at a selected axialposition; the second of each pair of working cylinders comprises arespective axial end opening extending through the closeable outer endthereof, each axial end opening communicating with the second end plateportion of the external stator; the at least one inlet passagewaycomprises a radial inlet port at the selected axial position, the radialinlet port communicating with each of the radially inwardly directedopenings exactly once during each rotation of the block; the at leastone exhaust passageway comprises an exhaust port at the selected axialposition, the exhaust port communicating with each of the radiallyinwardly directed openings exactly once during each rotation of theblock; and wherein the second end plate portion further comprises: atleast one fluid intake passageway communicating with each of the axialend openings exactly once during each rotation of the block; and atleast one fluid exhaust passageway communicating with each of the axialend openings exactly once during each rotation of the block; whereby theaxial piston rotary power device is adapted to function as one of atwo-cycle fluid-driven compressor and a two-cycle fluid-driven pump. 20.The axial piston rotary power device of claim 19 wherein each of thefluid intake and fluid exhaust passageways comprises a semicirculargroove formed in the inner face of the second end plate portion of theexternal stator.
 21. The rotary power device of claim 1 wherein theinternal stator portion further comprises at least one axial lubricationpassageway for supplying lubricant fluid to a clearance space betweenthe central stator portion and the block.
 22. The rotary power device ofclaim 1 wherein the external stator portion comprises at least onepassageway for supplying lubricant fluid to and for withdrawinglubricant fluid from the annular rotor recess.
 23. A four-cycle internalcombustion engine having an output shaft fixedly attached to acylindrical block rotatable about an axis of the shaft and receivedwithin an external portion of a stator, the external portion of thestator having an axially undulating guide surface fixed thereto, theaxially undulating guide surface comprising a first pair of points atwhich the surface is a maximum axial distance from a first selectedaxial position and a second pair of points at which the surface is aminimum axial distance from the first selected axial position; thecylindrical block comprising: a central cylindrical bore extendingthrough the block along an axis of the shaft; a medial annular recessextending through an outer cylindrical wall of the cylindrical block; aselected number of cylindrical cavities parallel to the shaft anddisposed at a single radial distance from the axis, each cylindricalcavity comprising a pair of working cylinders axially spaced apart onopposite sides of the medial annular recess; each working cylinderhaving an inner end proximal the medial annual recess and open thereto,each working cylinder having a closeable outer end distal from themedial annular recess, each of the working cylinders having a respectiveradially inwardly directed opening adjacent the closeable end thereof,the radially inwardly directed opening of one working cylinder in eachpair thereof communicating with the central cylindrical bore at thefirst selected axial position, the radially inwardly directed openingassociated with the second working cylinder in the each pair thereofcommunicating with the central cylindrical bore at a second selectedaxial position; the selected number of piston assemblies, each pistonassembly slidably received in a respective cylindrical cavity; eachpiston assembly comprising two axially spaced apart piston heads havinga respective middle portion extending therebetween, each middle portioncomprising at least a respective pair of rotatable roller cam followersfor following the axially undulating guide surface received in themedial annual recess, each middle portion further comprising arespective cam follower pin for slidably engaging a respective axialgroove formed in a wall of the respective cylindrical cavity; the enginefurther comprising an internal portion of the stator received in thecylindrical bore of the cylindrical block, the internal portion of thestator having a plurality of passageways formed therein, each of thepassageways comprising a channel parallel to the axis of the shaft, eachof the channels communicating with at least one respective radial portformed in the internal stator at one of the selected axial positions, atleast one of the plurality of passageways comprising an inletpassageway, a second at least one of the plurality of passagewayscomprising an exhaust passageway, and two of the passageways comprisingignition passageways comprising respective ignition ports, each of theignition ports comprising means for receiving an igniter therein. 24.The four-cycle internal combustion engine of claim 23 wherein theaxially undulating guide surface comprises a protrusion from an innersurface of the external portion of the stator.
 25. The four-cycleinternal combustion engine of claim 23 wherein the axially undulatingguide surface comprises two separate portions attached to each otheralong a line that is a diagonal of the cylindrical block.
 26. Thefour-cycle internal combustion engine of claim 23 wherein the means forreceiving an igniter comprises a threaded portion of each ignition port.27. A two-cycle internal combustion engine having an output shaftfixedly attached to a cylindrical block rotatable about an axis of theshaft and received within an external portion of a stator having anaxially undulating guide surface fixed thereto, the axially undulatingguide surface comprising exactly one point at which the surface is amaximum axial distance from a first selected axial position and exactlyone point at which the surface is a minimum axial distance from thefirst selected axial position; the cylindrical block comprising: anouter wall comprising a medial annular recess for receiving the axiallyundulating guide surface; a central cylindrical bore for receiving aninternal portion of the stator, the central cylindrical bore extendingthrough the block along the axis; a selected number of cylindricalcavities parallel to the shaft and disposed at a single radial distancefrom the axis, each cylindrical cavity further comprising a pair ofworking cylinders axially spaced apart on opposite sides of the medialannular recess; each working cylinder having an inner end proximal themedial annual recess and open thereto, each working cylinder having acloseable outer end distal from the medial annular recess, each of theworking cylinders having a respective radially inwardly directed outerend opening adjacent the closeable end thereof, the outer end opening ofa first working cylinder in each pair thereof communicating with thecentral cylindrical bore at the first selected axial position, the outerend opening associated with the second working cylinder in the each pairthereof communicating with the central cylindrical bore at a secondselected axial position; each of the working cylinders further having arespective radially inwardly directed medial end opening adjacent theinner end thereof, the respective medial end opening of the firstworking cylinder in each pair thereof communicating with the centralcylindrical bore at a third selected axial position closer to the firstaxial position than to the second, the respective medial end opening ofthe second working cylinder in each pair thereof communicating with thecentral cylindrical bore at a fourth selected axial position closer tothe second axial position than to the first; each of the cylindricalcavities further comprising a respective axial groove extending betweenits associated pair of working cylinders; the selected number of pistonassemblies, each piston assembly slidably received in a respectivecylindrical cavity; each piston assembly comprising two axially spacedapart piston heads having a respective middle portion extendingtherebetween, each middle portion comprising at least a respective pairof rotatable roller cam followers for following the axially undulatingguide surface received in the medial annual recess, each middle portionfurther comprising a respective cam follower pin for slidably engaging arespective axial groove formed in a wall of the respective cylindricalcavity; wherein the engine further comprises: a plurality of passagewaysformed in the internal stator, each of the passageways comprising achannel parallel to the axis of the shaft, each of the channelscommunicating with at least one respective radial port formed in theinternal stator at one of the selected axial positions, at least one ofthe plurality of passageways comprising an inlet passageway, a second atleast one of the plurality of passageways comprising an exhaustpassageway, and at least one of the plurality of passageways comprisinga fuel injection passageway.
 28. The two-cycle internal combustionengine of claim 27 wherein the axially undulating protruding guidesurface comprises a protrusion extending from an inner surface of amiddle portion of the external portion of the stator.
 29. The two-cycleinternal combustion engine of claim 27 wherein the axially undulatingguide surface is comprised of two separate portions joined along a linethat is a diagonal of the cylindrical block.
 30. An axial piston rotarypower device operable as one of a compressor and a pump, the devicehaving an input shaft fixedly attached to a cylindrical block rotatableabout an axis of the shaft within an external portion of a stator, theexternal portion of the stator comprising a middle portion having agenerally cylindrical interior and two end plate portions spaced apartby the middle portion; wherein the cylindrical block comprises: an outerwall comprising a medial annular recess for receiving an axiallyundulating guide surface portion of the external portion of the statorand a central cylindrical bore for receiving an internal stator portionof the stator, the central cylindrical bore extending through the blockalong an axis of the shaft; a selected number of cylindrical cavitiesparallel to the shaft and disposed at a single radial distance from theaxis thereof, each cavity comprising a pair of working cylinders axiallyspaced apart on opposite sides of the medial annular recess, eachworking cylinder having an inner end proximal the medial annual recessand open thereto, each working cylinder having a closeable outer enddistal from the medial annular recess, each of the working cylindershaving a respective radially inwardly directed opening adjacent thecloseable end thereof, the respective radially inwardly directed openingof one working cylinder in each pair thereof communicating with thecentral cylindrical bore at a first selected axial position, therespective radially inwardly directed opening associated with the secondworking cylinder in the each pair thereof communicating with the centralcylindrical bore at a second selected axial position; the selectednumber of piston assemblies, each piston assembly slidably received in arespective cylindrical cavity; each piston assembly comprising twoaxially spaced apart piston heads having a respective piston middleportion extending therebetween, each piston middle portion comprising atleast a respective pair of rotatable roller cam followers for followingthe axially undulating guide surface received in the medial annualrecess, each piston middle portion further comprising a respective camfollower pin for slidably engaging a respective axial groove formed in awall of the respective cylindrical cavity; wherein the compressorfurther comprises: a plurality of passageways formed in the internalstator portion, each of the passageways comprising a channel parallel tothe axis of the shaft, each of the channels communicating with at leastone respective radial port formed in the internal stator at one of theselected axial positions, at least one of the plurality of passagewayscomprising an inlet passageway, a second at least one of the pluralityof passageways comprising an exhaust passageway; and wherein the axiallyundulating guide surface has a selected number, equal to or greater thanone, of points at which the surface is a maximum axial distance from thefirst selected axial position and the selected number of points at whichthe surface is a minimum axial distance from the first selected axialposition.